D. This is to “proofread” the DNA
Fatty acids are mostly composed of chains of carbon and hydrogen. Fatty acids without double bonds are "saturated" with hydrogen. When a fatty acid has one double bond, hydrogen is released therefore the fatty acid is "monounsaturated". When a fatty acid has two or more double bonds, then the fatty acid is "polyunsaturated". Unsaturated fatty acids are usually takes in the form of oils as they are liquid in room temperature (in contrast to saturated fatty acids which are solid in room temperature). Unsaturated fatty acids are usually found in plant based fats such as oils. Therefore the answer to this question is sunflower oil.
